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1.
Patricia A. Miguez Stephen A. Tuin Adam G. Robinson Joyce Belcher Prapaporn Jongwattanapisan Kimberly Perley Vinicius de Paiva Gon«alves Arash Hanifi Nancy Pleshko Elisabeth R. Barton 《International journal of molecular sciences》2021,22(6)
This study evaluated the direct effect of a phytochemical, hesperidin, on pre-osteoblast cell function as well as osteogenesis and collagen matrix quality, as there is little known about hesperidin’s influence in mineralized tissue formation and regeneration. Hesperidin was added to a culture of MC3T3-E1 cells at various concentrations. Cell proliferation, viability, osteogenic gene expression and deposited collagen matrix analyses were performed. Treatment with hesperidin showed significant upregulation of osteogenic markers, particularly with lower doses. Mature and compact collagen fibrils in hesperidin-treated cultures were observed by picrosirius red staining (PSR), although a thinner matrix layer was present for the higher dose of hesperidin compared to osteogenic media alone. Fourier-transform infrared spectroscopy indicated a better mineral-to-matrix ratio and matrix distribution in cultures exposed to hesperidin and confirmed less collagen deposited with the 100-µM dose of hesperidin. In vivo, hesperidin combined with a suboptimal dose of bone morphogenetic protein 2 (BMP2) (dose unable to promote healing of a rat mandible critical-sized bone defect) in a collagenous scaffold promoted a well-controlled (not ectopic) pattern of bone formation as compared to a large dose of BMP2 (previously defined as optimal in healing the critical-sized defect, although of ectopic nature). PSR staining of newly formed bone demonstrated that hesperidin can promote maturation of bone organic matrix. Our findings show, for the first time, that hesperidin has a modulatory role in mineralized tissue formation via not only osteoblast cell differentiation but also matrix organization and matrix-to-mineral ratio and could be a potential adjunct in regenerative bone therapies. 相似文献
2.
This paper focuses on the configuration design of flexure hinges with a prescribed compliance matrix and preset rotational center position. A new method for the topology optimization of flexure hinges is proposed based on the adaptive spring model and stress constraint. The hinge optimization model is formulated by maximizing the bending displacement with a spring while optimizing the compliance matrix to a prescribed value. To avoid numerical instability, an artificial spring is used as an auxiliary calculation, and a new strategy is developed for adaptively adjusting the spring stiffness according to the prescribed compliance matrix. The maximum stress of flexure hinge is limited by using a normalized P-norm of the effective von Mises stress, and a position constraint of rotational center is proposed to predetermine the position of the rotational center. In addition, to reduce the error of the stress measurement, a simple but effective filtering method is presented to obtain a complete black-and-white design. Numerical examples are used to verify the proposed method. Topology results show that the obtained flexure hinges have the prescribed compliance matrix and preset rotational center position while also meeting the stress requirements. 相似文献
3.
Matrix Manipulation of Directly-Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering
Fei Li Yang Liu Guozheng Shi Wei Chen Renjun Guo Dong Liu Yaohong Zhang Yongjie Wang Xing Meng Xuliang Zhang You Lv Wei Deng Qing Zhang Yao Shi Yifan Chen Kai Wang Qing Shen Zeke Liu Peter Müller-Buschbaum Wanli Ma 《Advanced functional materials》2021,31(45):2104457
The direct-synthesis of conductive PbS quantum dot (QD) ink is facile, scalable, and low-cost, boosting the future commercialization of optoelectronics based on colloidal QDs. However, manipulating the QD matrix structures still is a challenge, which limits the corresponding QD solar cell performance. Here, for the first time a coordination-engineering strategy to finely adjust the matrix thickness around the QDs is presented, in which halogen salts are introduced into the reaction to convert the excessive insulating lead iodide into soluble iodoplumbate species. As a result, the obtained QD film exhibits shrunk insulating shells, leading to higher charge carrier transport and superior surface passivation compared to the control devices. A significantly improved power-conversion efficiency from 10.52% to 12.12% can be achieved after the matrix engineering. Therefore, the work shows high significance in promoting the practical application of directly synthesized PbS QD inks in large-area low-cost optoelectronic devices. 相似文献
4.
聚合物基表面微结构在软体机器人、柔性电子器件、仿生机械、生物医学、组织工程等领域有着广泛的应用,将逐面式制造技术应用于聚合物基表面微结构的制造过程可解决传统微压印、光刻、逐点和逐线式制造方法加工周期长、效率低、大面积表面微结构制造脱模难等问题。发展聚合物基表面微结构的逐面式制造技术是当前先进制造技术的研究热点之一,具有广阔的应用前景。首先在阐述了常见的聚合物基表面微结构设计及其制造材料的基础上,重点论述了光刻、纳米压印、数字光投影式3D打印、能场辅助制造、自组装制造等五类逐面式成形制造技术方面的最新研究进展,包括各种制造技术的制造原理、工艺特点及表面微结构的典型应用等。最后,总结预测了聚合物基表面微结构设计、制造及应用方面的发展趋势,并对聚合物基表面微结构的逐面式成形制造技术的未来发展进行了展望。 相似文献
5.
To advance organ-on-a-chip development and other areas befitting from physiologically-relevant biomembranes,a microfluidic platform is presented for synthesis of biomembranes during gelation and investigation into their role as extracellular matrix supports.In this work,high-throughput studies of collagen,chitosan,and collagen-chitosan hybrid biomembranes were carried out to characterize and compare key properties as a function of the applied hydrodynamic conditions during gelation.Specifically,depending on the biopolymer material used,varying flow conditions during biomembrane gelation caused width,uniformity,and swelling ratio to be differently affected and controllable.Finally,cell viability studies of seeded fibroblasts were conducted,thus showing the potential for biological applications. 相似文献
6.
研究了遭受网络攻击的双层结构多智能体系统的一致性问题。针对包含领导层和跟随者层的双层网络结构的多智能体系统,考虑了如下情况:领导层相邻智能体之间为友好合作关系,跟随者层相邻智能体之间既包含友好合作也包含对抗竞争关系,同时领导层与跟随者层中部分对应智能体之间存在牵制关系。分析了受网络攻击的领导层多智能体系统、跟随者层多智能体系统和双层网络结构多智能体系统的节点之间的一致性关系。基于线性矩阵不等式(LMI)、李雅普诺夫稳定性理论和图论等相关知识给出了领导层多智能体系统节点间实现一致,跟随者层多智能体系统节点间实现二分一致,以及双层结构的多智能体系统之间实现点对点二分一致的充分性判据。最后,给出了具体的数值仿真例子,实现了遭受网络攻击的双层结构多智能体系统的一致性,验证了所给出的判据的有效性。 相似文献
7.
将小波变换多尺度理论用于分析确定共生矩阵最佳步长参数值,利用小波变换对原始图像进行分解,根据具体纹理图像,选择合适小波子图像(近似图像或其细节子图像)进行纹理分析,通过计算分解图像的纹理特征参数(对比度)确定最佳步长参数。当步长参数为最优值时,计算所得纹理特征参数值将处于周期极值位置,其利于纹理分析。相对于原始图像,分解图像数据量小,在寻优共生矩阵最佳步长参数时,计算复杂度及时间消耗都有所降低。实验验证,基于小波分解图像所得最佳步长参数值是精确的。 相似文献
8.
Carla Marina Santos Feldhaus Roseli Künzel Máximo Siu Li Ana Paula de Azevedo Marques 《Journal of the American Ceramic Society》2021,104(10):5192-5204
The compounds based on calcium molybdate (CaMoO4) are the subject of extensive research due to their excellent optical properties and a broad range of potential technological applications. In this work, we report a systematic study of CaMoO4:Tm3+ phosphors synthesized by coprecipitation and processed in a microwave-hydrothermal system at low temperature (100°C) and stirring. The effect of the Tm3+ doping content (0%–12%) is studied in full detail to understand their role in the CaMoO4:Tm3+ morphological, structural, and luminescent properties. The X-ray diffraction, Raman, and Fourier Transform Infrared spectroscopic techniques revealed that all the prepared powders have a tetragonal crystal structure with a distinct density of cation vacancies and structural disorders. The band gap remains almost constant for doping levels lower than 8%, but it narrows strongly for powders doped with 12% Tm3+ ions. The designed phosphors have shown two emission bands in which intensity depends on the Tm3+ ions doping level. For doping levels lower than 2%, the photoluminescence profile displays a broad emission band peaking at 543 nm (green). For concentrations higher than 4%, the band centered at 543 nm decreases in intensity and the near-infrared emission band at around 800 nm, assigned to 3F3, 3H4 → 3H6 transitions from Tm3+ ion, become more intense. The outcomes of this work reveal that appropriated Tm3+ ions doping levels can be applied to suppress the PL emission in the visible range and improve that in the near-infrared region in CaMoO4-based materials. 相似文献
9.
白光LED (light-emitting diode)因其优异的发光性能被誉为是第四代固体照明光源。本文以量子效率作为核心参数,以暖白光为最终目标,分别对蓝、绿、红三基色稀土掺杂无机荧光粉和单一基质单掺、共掺、多掺的暖白光荧光粉的研究现状进行调研。结果表明,高量子效率的近紫外激发蓝色荧光粉其激活离子主要为Eu2+、Ce3+,绿色荧光粉为Tb3+和Eu2+,红色荧光粉为Eu3+和Eu2+。现有的单一基质暖白光荧光粉仍然存在诸多技术瓶颈,如:红光不足、显色指数偏低、量子效率偏低等。基于此,建议从已有的高效红粉出发制备单一基质白光荧光粉,以消除光谱中缺乏红色成分这一难题,并适当引入除Mn之外的过渡金属元素,同时加强对基质动力学理论,以及基质和稀土之间的电子耦合作用动力学理论的研究,期望能实现稀土掺杂无机荧光粉的设计计算与可控制备。 相似文献
10.
现有的高斯响应矩阵在对高分辨率γ能谱进行重建时,极易出现假峰、峰位漂移等问题。本文针对测量条件(温/湿度、电压波动等)微弱变化引起峰位扰动进而影响高斯响应矩阵重建结果准确度的问题,通过引入微扰动修正因子,对现有高斯响应矩阵进行修正。采用IAEA重峰分解测试谱及GMX40P高纯锗探测器实测能谱对修正前后的高斯响应矩阵进行谱线解析测试。结果表明:通过修正后响应矩阵重建的能谱,其峰位与实际峰位保持一致,净峰面积的相对偏差分别低于1025%和550%。 相似文献